The prognostic value of multidetector coronary CT angiography for the prediction of major adverse cardiovascular events: a multicenter observational cohort study.

To assess the prognostic value of coronary artery stenosis identification by coronary computed tomographic angiography (CCTA) for the prediction of major adverse cardiac events (MACE) in a multicenter prospective cohort study. We performed a prospective multicenter observational cohort study of symptomatic patients with suspected or known coronary artery disease (CAD) (n = 172; 57% male) undergoing CCTA in accordance to ACC/AHA Appropriateness Criteria from 4 sites in and around Paris, France, and followed for a mean duration of 22.0 +/- 4.5 months (interquartile range 18-26 months). Coronary arteries by CCTA were interpreted by physicians blinded to the patient characteristics for the presence or absence obstructive (>or=70% luminal diameter stenosis), as well as for plaque composition categorized as non-calcified, calcified or "mixed." MACE was defined as death, non-fatal myocardial infarction, unstable angina or target vessel revascularization. MACE event rates were compared between patients with or without obstructive plaque and with differing plaque compositions. MACE event rates were significantly higher in patients with obstructive coronary artery stenosis by CCTA compared to those without (61.1% vs. 3.9%, P < 0.01). In patients with obstructive stenosis, mixed (83.3% vs. 25.3%, P < 0.01) and calcified (94.4% vs. 50.7%, P < 0.01) plaque presence was significantly higher than in patients without obstructive stenosis, with no differences in prevalence of non-calcified plaque (27.8% vs. 20.8%, P = NS). For MACE, the negative predictive value of no observed coronary artery plaque was 100% in the follow-up period. In this prospective multicenter study of symptomatic patients with suspected or known CAD undergoing CCTAs interpreted by imagers blinded to patient characteristics, CCTA presence of plaque severity and composition successfully identifies patients at risk for incident MACE events. Importantly, a negative CCTA portends an extremely low risk for incidence MACE.

Arterio-venous fistula: two cases realistic numerical blood flow simulations.

Patients with ESRD "End-stage renal disease" require hemodialysis. The most desirable form of vascular access is the arterio-venous fistula (AVF). It is placed surgically joining an artery and a vein together. We propose an investigation protocol to understand the correlation between hemodynamics in this vessel and the associated clinical complications. Realistic 3D reconstruction of the fistula is the result of segmenting CT angiography images for two cases. Then the geometrical model is preprocessed by hybrid meshing and CFD results are confronted with medical image data such as calcifications.

Investigations into the relationship between hemodynamics and vascular alterations in an established arteriovenous fistula.

Arteriovenous fistula are specific vessels created by a vascular operation in order to provide sufficient blood access for extracorporeal circulation in hemodialysis. They are subject to numerous pathologies that may be caused by hemodynamic effects. To better understand these effects, a specific patient's arteriovenous fistula was reconstructed from computed tomography angiography. Computational fluid dynamics software made it possible to solve fluid mechanics equations under physiological conditions. An accurate map of unsteady velocity profiles and wall shear stress was drawn up. The computed velocity profiles were successfully confronted with Echo Doppler investigation. Selected regions with or without calcification, the end stage of wall alteration, were examined in terms of the mechanical constraints generated by blood flow. In contrast with other authors, we did not observe any association between calcification and areas of oscillating shear stress. Nevertheless, a statistical analysis of the whole vessel envelop and specific sites of calcification suggested a potential association between calcification and high temporal wall shear stress gradients.

[Radiological reports and computer-assisted diagnosis]. / Comptes rendus radiologiques et diagnostics assistés par ordinateur.

Computers, particularly personal computers, have improved the quality and rapidity of radiology reports. Radiology reports are part of the information processing chain and should be found by means of a data base. The computer can help the radiologist to write the report by improving the man-machine interface: graphic interface, pointing tools (mouse, trackball), computer without keyboard, vocal recognition. These computer systems have larger and larger storage capacities (hard disks, optical disks). They can provide a contextual aid during report writing, when the editors use digital supports for their publications.

Imaging of the digital arteries: digital subtraction angiography versus conventional arteriography.

A retrospective study of 95 patients was undertaken to compare digital subtraction angiography (DSA) and conventional arteriography of the hand. Eighty patients had conventional angiography and 15 had DSA. In comparison with conventional angiography, DSA is more cost-efficient and facilitates outpatient angiography. It provides images as acceptable as those of conventional angiography. We conclude that intra-arterial DSA is now the procedure of choice for angiographic mapping of the digital arteries.

[Arteriographic data in chronic ischemia of the hand. Study of 62 cases]. / Données de l'artériographie dans les ischémies chroniques de la main. Etude de 62 cas.

The arteriograms of sixty-two patients with chronic ischemia of the hand and fingers were reviewed. Twelve patients were considered to have Raynaud's disease. Thoracic outlet syndrome caused ischemic symptoms in thirteen patients. Arteriosclerosis obliterans affected twenty-two patients. The signs of arteriosclerosis are described including irregular constrictions, multiple occlusions and the corkscrew pattern of the collateral arteries. The differential diagnosis includes thromboangiitis obliterans and collagen vasculitis.